With Britain on the verge of quitting the European Union, the country's financiers are asking the U.K. government to revamp regulations to attract global business.

Watchdogs should have the power "to make the U.K. a better place to do business" through a new mandate to support London's financial hub against rivals, according to the International Regulatory Strategy Group, a panel sponsored by the City of London Corp., which administers the financial district, and TheCityUK lobby groups.

The financial industry has faced an uphill battle to get its way in the negotiations over Brexit since the 2016 referendum. Much cross-border business depends on keeping close alignment with the EU's rules, yet the U.K. government has signaled its willingness to break away on several fronts.